The present invention relates to a dielectric ceramic composition and a multilayer ceramic capacitor including a dielectric layer having the dielectric ceramic composition. The present invention particularly relates to the dielectric ceramic composition having good IR property and highly accelerated lifetime.
Recently, as the electronic circuit has become highly densified, the electronic component is demanded to be more compact, and the multilayer ceramic capacitor has rapidly become more compact and has larger capacity, further the purpose of use has become wider, thus various properties are demanded.
For example, a mid-high voltage capacitor which is used at a high rated voltage (for example 100 V or higher) is suitably used for ECM (Engine Electric Computer Module), a fuel injection device, an electric controlled throttle, an inverter, a convertor, HID headlamp unit, a battery control unit for hybrid engine, a digital steel camera, and the like.
In case of using at a high rated voltage as mentioned in the above, it is used under a high electric field intensity, but when the electric field intensity increases, the specific permittivity and the insulation resistance decrease, hence as a result, an effective capacity or a reliability under the used environment may decrease.
For example, Patent document 1 discloses a multilayer ceramic capacitor having a dielectric layer made of a dielectric particle having a core-shell structure. This dielectric particle has a concentration gradient of a sub component at a shell part, and a maximum value of the sub component concentration is found near the particle boundary and near a boundary between the shell part and the core part. The multilayer ceramic capacitor using this dielectric particle has good capacity-temperature property and lifetime property.
However, the multilayer ceramic capacitor described in Patent document 1 exhibited insufficient properties under a high electric field intensity such as when applying DC voltage and the like thus further improvement of the properties were demanded.
Patent document 1: JP Patent Application Laid Open No. 2011-256091